1. Field of the Invention
The present invention relates to an electrode structure of a lamp, and more particularly to an electrode structure that is adaptive for easily fixing an electrode and stably implementing a soldering operation of the electrode, and a method for forming the electrode structure.
2. Discussion of the Related Art
In general, because liquid crystal display (LCD) devices are thin, low weight, and have low power consumption, they are increasingly being used as the displays of portable devices. Liquid crystal display devices are widely used as flat panel displays in office automation equipment such as laptop and desktop computers, in audio/visual equipment, and in other types of equipment.
LCD devices operate by controlling the transmittance of light beams emitted by a backlight unit through a liquid crystal display panel. The liquid crystal display panel includes a plurality of liquid crystal cells arranged into a matrix and a plurality of control switches for supplying video signals to the corresponding liquid crystal cells in order to display the desired video image on a screen.
Liquid crystal display devices are not self-luminous and require a light source or backlight to provide a visible video image. LCD backlights are classified as direct type or an edge type depending on the location of the light source or lamp relative to the LCD flat panel. In an edge type backlight, a lamp is installed near an outer part of the flat panel, and light rays from the lamp are directed over the surface of the flat panel by use of a transparent light guide. In a direct type backlight, a plurality of lamps are disposed in a plane with the light rays emitted from the lamps directly incident to the LCD flat panel.
The lamp used in the LCD backlight may be a cold cathode fluorescent light (CCFL) type as shown in FIG. 1. The CCFL lamp employs an electrode contained within the two ends of a glass tube for connection of supply power. The backlight lamp may be an external electrode fluorescent light (EEFL) type where power is supplied to a metal electrode which encompasses both ends of a glass tube of the lamp as shown in FIG. 2.
Referring to FIG. 1, a cold cathode fluorescent lamp 1 of the related art includes a glass tube 2 in which a light-emitting material is sealed; an electrode 3 formed at the ends of a glass tube 2; and an electrode line 4 which penetrates the glass tube 2 to connect to the electrode 3.
The electrode line 4 of the CCFL lamp 1 is connected to a power source to supply energy to the electrode 3. The manufacturing processes in the related art for penetrating the glass tube 2 to connect the electrode line 4 to the electrode 3 are complex and frequently produce a defective lamp. The EEFL lamp 5 shown in FIG. 2 has been proposed to avoid the need to penetrate the glass tube 2 to connect to the electrode 3
Referring to FIG. 2, an EEFL lamp 5 includes a glass tube 6 within which a light-emitting material is sealed and an electrode 7 formed in a cylindrical shape covering each end of the glass tube 6. Supplying a source of high voltage to the electrodes 7 of the EEFL lamp 5 causes the light-emitting material within the glass tube 6 to emit light.
Because the electrode 7 of the EEFL lamp 5 of the related art is external to the glass tube 6 the electrode 7 may become separated from the class tube rendering the lamp inoperable. The electrode 7 may be attached to an end of glass tube 6 in a soldering operation. The soldering operation requires the application of a high temperature to the glass tube 6 to melt the solder. An operator performing the soldering operation may accidentally damage the glass 6 tube while applying the high temperature. If the operator applies insufficient heat or otherwise fails to properly complete the soldering operation, the electrode 7 and the glass tube 6 may become separated producing an inoperable lamp.